Field of the Invention
This invention relates to a cooling and conveying apparatus having spiral screw vanes for use in a cooling process to be performed in treatment of poultry carcasses for consumption.
Description of the Related Art
A poultry carcass is sequentially subjected to a bleeding treatment, a scalding treatment and a feather plucking treatment, and then to evisceration. The poultry carcass is washed as pretreatment, and then the poultry carcass having a body temperature of 38 to 42° C. is cooled to a target temperature of 5 to 7° C. in order to prevent propagation of bacteria. This cooling is generally performed by a continuous immersion cooling technique that is highly efficient. Specifically, according to this cooling technique, a bactericide such as sodium hypochlorite is added to a coolant of 2 to 3° C. in chiller tank. Poultry carcasses which are sequentially transported are introduced into the chiller tank, immersed in the coolant containing the bactericide for a certain period of time so that the poultry carcasses are cooled and sterilized.
The inventors of this invention have proposed a poultry carcass cooling apparatus having spiral screw vanes incorporated therein and a cylindrical housing filled with a coolant, and designed to rotate the screw vanes about an axis so that a poultry carcass is cooled while being conveyed from the inlet to the outlet of the cylindrical housing (Japanese Patent Application Publication Nos. 2008-295446 and 2010-136651). This apparatus, unlike conventional ones, is of an enclosed type, not an open type, and the number of poultry carcasses that can be accommodated is increased by setting the coolant level in the tank higher, and thus the space required to install the apparatus is reduced. This apparatus further provides advantages that traceability of the poultry carcasses can be ensured by sequentially transporting the poultry carcasses from the inlet to the outlet of the housing while cooling the carcasses, and CIP cleaning can be performed after completion of the treatment by providing flushing nozzles for spraying wash water in the inside of the housing.
According to the CIP cleaning method described in Japanese Patent Application Publication Nos. 2008-295446 and 2010-136651, flushing nozzles are provided on the rotating shaft of the screw vanes and on the inner wall of the housing. Wash water is sprayed from the flushing nozzle provided on the rotating shaft toward the inner wall of the housing to clean the sides of the carcasses facing the inner wall of the housing, while wash water is sprayed from the flushing nozzle provided on the inner wall of the housing toward the rotating shaft to clean the sides of the carcasses facing the rotating shaft.
According to the CIP cleaning method described in Japanese Patent Application Publication Nos. 2008-295446 and 2010-136651, a flushing nozzle is provided for every two pitches of the screw vanes on the rotating shaft and the inner wall of the housing. The screw vanes having spiral complicated curved vanes often obstruct the wash water sprayed from the flushing nozzles provided on the rotating shaft toward the inner wall of the housing depending on positions where the flushing nozzles are placed. Additionally, depending on positions where the flushing nozzles provided on the inner wall of the housing are placed, the curved surfaces of the screw vanes possibly form blind areas where no wash water sprayed from the flushing nozzles reaches. Therefore, the CIP cleaning method described in Japanese Patent Application Publication Nos. 2008-295446 and 2010-136651 may be unable to clean the screw vanes, the rotating shaft and the inner wall of the housing sufficiently in a short period of time.